The exploit involves shorting out a pin in the right Joy-Con connector which forces the system into USB recovery mode. Then a command is sent with a large `length` value which allows the attacker to send a large control request which in turn causes a buffer overflow allowing the attacker's code to be copied over to Switch's application memory.

All of these happens in the Boot ROM so this is something that can only be patched during the manufacturing process. In other words, once it is in user's hand (current estimation is more than 14.8 mil), Nintendo can do nothing about it unless they issue a recall.

Quote:If your Switch catches fire or turns into an Ouya, it's not our fault. It's stupidly easy to blow up embedded platforms like this with bad software (e.g. all voltages are software-controlled). We already caused temporary damage to one LCD panel with bad power sequencing code. Seriously, do not complain if something goes wrong.

Nintendo would probably implement some mechanism to ban the user from their online services or the user's account if it detects the Switch is modified though, so users aren't exactly free to do whatever they want. Also, word on the street is that Nintendo is shipping a new hardware revision soon which would likely patch this vulnerability.